This invention relates to a process for preparing a gel composition based on an inert organic liquid having gas transporting capability. The invention also relates to the resulting gel composition, which gel has a variety of medical, cosmetic, industrial and other uses.
Many inert organic liquids are known which have gas transporting capabilities, that is, have high solubility for gases such as oxygen, nitrogen, carbon dioxide, the inert gases, and mixtures of gases including air. Among the many classes of inert organic liquids having such properties are water immiscible, liquid fluorocarbons and low viscosity silicone oils. These classes of liquids are described in U.S. Pat. No. 3,850,753 issued Nov. 26, 1974 to Chibata et al for the culturing of aerobic microorganisms. However, the patent does not mention emulsions or gel formulation therewith.
Other perfluorocarbons, emulsions thereof and their properties are described in the following U.S. Pat. Nos.: 4,220,606, R. E. Moore, Sept. 2, 1980; 4,143,079, R. E. Moore, Mar. 3, 1979; 4,105,798, R. E. Moore et al., Aug. 8, 1978; 4,041,086, Moore et al., Aug. 9, 1977; 3,911,138, L. C. Clark, Jr., Oct. 7, 1975; 3,962,439, K. Yokoyama et al., June 8, 1976; 3,993,581, K. Yokoyama et al., Nov. 23, 1976; 4,187,252, R. J. Lagow et al., Feb. 5, 1980; 4,110,474, R. J. Lagow et al., Aug. 29, 1978; and 3,641,167, Moore et al., Feb. 8, 1972. In U.S. application Ser. No. 52,041 filed June 25, 1979, now abandoned, by David C. White, superseded by Ser. No. 228,642 filed Jan. 26, 1981, now U.S. Pat. No. 4,366,169, a method of treating wounds, such as a burn, is disclosed wherein the burn is contacted with a liquid perfluorocarbon, directly or supported on a sponge, or in the form of a foam, spray or gel. There is no disclosure in the White application of any specific gel composition or of any process for preparing a gel composition.
The information contained in the aforementioned patents is incorporated herein by reference.
Techniques are known for separating various particulate materials from aqueous media in which they are formed or treated. For example, U.S. Pat. No. 2,107,839 describes isolation in dry powder form of the therapeutic agent derived from the natural latex of the Lactuca plant, by allowing the emulsion to break by standing, and then filtering or centrifuging to separate the aqueous solution containing the active constituent.
Further, a variety of gels are known which are produced from aqueous suspensions by precipitation, decantation, filtration (including membrane filtration) and centrifugation. The products are commonly isolated as dry materials and are called "gels" apparently because they revert to a semi-solid, somewhat plastic or swollen state upon contact with water. They exhibit high porosity and are used for a variety of purposes, depending on their origin, porosity and swellability. Among such materials are the gelatin-carboxymethyl cellulose complexes of U.S. Pat. No. 2,824,092; the soybean proteinate hydrogels of U.S. Pat. No. 3,218,307; the gelatinous flocculent obtained by fermenting a natural polysaccharide and then centrifuging, as in U.S. Pat. No. 3,096,293; hydroxy-lower alkyl ethers of galactomannans produced as stable, dry hydrocolloids by filtration and centrifugation, as in U.S. Pat. No. 3,326,890; the dry, agarose gels of U.S. Pat. No. 3,527,712; and the silica gels produced as in U.S. Pat. Nos. 3,346,507 and 3,560,400.
None of these patents, however, teach or suggest concentration of an emulsion accompanied by formation of a gelatinous material, nor preparation of a gelatinous material containing an inert, water-immiscible organic liquid gas transporting agent.